How long have you had a clear bra on your Prii?

I've had mine on since new, April 05. A few things to consider:
1st, While the paint will be ok, large rocks will still dent the hood. While the dents are the kind you can get 'popped' out, I haven't had mine done as I figured it would destroy or ruin the bra
2nd, you can wax the bra, but I normally can get all bugs and tar off without using a tar/bug remover. Mine is a 3m product; each product could be different
3rd, bra or no bra, the Prius front end is lower than most non-sports cars, gutters, driveways. Check out the height of the Prius next to a mid-size SUV(Toyoda Highlander)... the complete Prius hood is no higher than where the SUV hood starts as a normal SUV non-painted grill takes all the road grit.
Finally, if you are going to get the bra, sooner is better... it will not hide any chip or blemish... just remember when it's done, you will be the only one finding those little things that you saw before..
good luck

 

I've only had the 3M bra on my Prius for a month but I've had it on a '01 Corvette for 6 years and it did not yellow one bit. The bra is a little more noticable on darker colors than lighter ones but unless I point it out to people on my Magnetic Grey no one sees it. It's great protection.

 

I also have the 3M product on my 02 Solara. Its been on since 2002 with no yellowing or any other problems. The car sat in the sun all day during the week for 4 years and was garaged at night. I liked it so much I have installed it on my 2008 Prius which I just got on July 4. Both cars are silver and unless the light is just right, the kits are basically invisible. Its an easy self install if you stick to mostly flat surfaces. No problem with the hood and front of the fenders. I tried a vinyl kit for the lights, but was not able to deal with the curvature. The more expensive kits are urethane which works much better. I found on the Solara that the metal surfaces have more problems with chipping than those of plastic so be sure to cover those.